I believe that aParted is intended for that purpose, but if your system is Intel or x86 based/capable I recommend booting to gParted live iso and working from there instead (http://sourceforge.net/projects/gparted/files/gparted-live-stable/0.24.0-2/gparted-live-0.24.0-2-i586.iso/download?use_mirror=skylineservers). That way you can access all local partitions (including the one where your Android OS lives) with superuser permissions. It goes without saying but I’ll say it anyway: BE CAREFUL when working in any partition editor with root access. It’s easy to hose the entire configuration if you don’t pay attention.